The present invention relates to a method and apparatus for managing power consumption in an electronic circuit.
Energy efficient system design in portable, battery-operated electronic devices has become increasingly important since energy consumption dictates the battery lifetime of a portable system, and this is a crucial performance metric for the success of any product in the consumer market. Thus, power management is becoming an indispensable part of the system infrastructure.
Dynamic power management (DPM) is a design methodology that enables the dynamic configuration or reconfiguration of a system for energy or power efficient computation. DPM techniques typically involve switching off or ‘slowing down’ idle parts of the system, and dynamically trading system performance for energy efficiency. DPM techniques provide ways to optimize and control the system power by tuning the performance of the individual system components to the varying workload.
In systems with a dynamically varying workload, that is, in systems that do not have to deliver a peak or maximum performance all of the time, the voltage and clock frequency can be controlled to optimize the power consumption of the system. This is known as dynamic voltage and frequency scaling (DVFS). United States Patent Application 20070266268 discloses a single instruction multiple data (SIMD) processor architecture whose operation is controlled by a local clock signal having a first frequency; a control processor adapted to control the operation of the SIMD processor architecture and generate signals to synchronize the operation of the processor array with the stream of data vectors. The operation of the control processor is controlled by a local clock signal having a second frequency; and power management means for adjusting the frequencies of the local clock signals in response to the synchronization signals generated by the control processor, thereby minimizing the power consumption of the SIMD processor architecture. However, this approach only adjusts frequency, leaving devices that may operate at low frequency even when not needed by the application code.
The power consumed by a chip belongs to two main components: dynamic switching power, and static or leakage power. These components can be independently managed. Conventional power management techniques rely on circuit level techniques. As fabrication technology moves to smaller geometries, static power dissipation is becoming critical. Static or leakage power is independent of the activities of the IC. Thus, for battery-driven electronics such as mobile phones, reducing the leakage power is important.